HFS3 Ver 2 onto 8L Audi S3 1.8 20VT

[pluto]

Hi Richard ,

Greetings,

Perhaps you can assist me

The ecu in question is ME7.5 Bosch

Thus far

I have linked the Injector negative to the green wire
Map sensor pin 4 to blue wire
Red wire to injector + ive

All of the above on the ECU cable.

On the rear end of the board ,
PWM - ive linked
Multiplier is at 1x
IDC is linked

Questions :
1. I want to have IDC as the primary , with MPS as the trigger - is this correct ? If so , which do I link on the back and which to I jump on the front ?

Thanks

[Richard L]

First of all, is your engine car a direct injection type?

It is better to put the red wire to a "pre-crank live" 12V switch rather the injector (+), it can be quite noisy there.

You only need to link the back if you want the system to run 70% IDC / 30% MPS. Otherwise, leave the solder link option.

[pluto]

Richard ,
\Greetings,

Normal port injection using the EV6 injectors if I believe.

So I have linked the back on IDC , is that correct ? Yes , I want to run the 70 % IDC/ 30 % MAP . In your expert opinion , would this set up give you better control ?

On the top side of the board , IDC is jumped as the trigger .

Thank you for your reply

[Richard L]

One more question, are they low impedance injectors? If they are you need to use green harness, but leave the gain as x1.

[pluto]

One more question, are they low impedance injectors? If they are you need to use green harness, but leave the gain as x1.

Hi ,

These are the normal high impedance injectors , like those found on the 8L A3 / Golf 4 GTI / B6 Audi's ect.

[pluto]

Richard ,
\Greetings,

Normal port injection using the EV6 injectors if I believe.

So I have linked the back on IDC , is that correct ? Yes , I want to run the 70 % IDC/ 30 % MAP . In your expert opinion , would this set up give you better control ?

On the top side of the board , IDC is jumped as the trigger .

Thank you for your reply

Richard ,

Greetings, any feedback on this ?

If I recall , the board came out of the box linked to IDC

[Richard L]

70 % IDC / 30% MAP is more suitable for stretched factory turbo where thermal load is more concentrated at the spool up area. Having more boost related delivery will help combating stress related knock. Often resulted in timing cut and power drop.

The configuration is totally reversible, no harm in trying it out.

[Quattro]

Richard ,

As usual we can count on you for the awnser ! Thanks ,

So to recap , please confirm

I want to use the 30 / 70 (map/idc) so,

Rear of Board
Only IDC linked or do I link both or unlink both ( I couldnt understand your explanation , sorry)
Front of board - independant of the rear , I choose map as the trigger to get injection during mid spool or peak boost. Its a small frame turbo so it spools hard and fast.

[Richard L]

Here are the possible combinations for the under-board solder mods:

1. IDC linked ............. 100% IDC (factory setting)
2. IDC + MPS (solder linked) ............ 70% IDC / 30% MPS
3. Cut IDC link + MPS (solder linked) ............... 100% MPS

[dscline]

You only need to link the back if you want the system to run 70% IDC / 30% MPS. Otherwise, leave the solder link option.

I have a question about this... is there any way to change this ratio, such as using resistors for the links, or some other trick? Is there any way to get to a 50/50 ratio, or some other ratio that puts more emphasis on MPS (other than 100% MPS)?

[Richard L]

You can alter the ratio by using different values of resistance but you need a soldering iron with a small tip. I can post a pictures here if you want to have a go.
You can upgrade to HFS4 for the ratio is infinitely variable.

[dscline]

Cool! If you could post some examples for a couple different ratios (like 50/50, and maybe a couple more to get an idea of how the resistance values scale), that would be great!

[dscline]

Hi, just wanted to follow up on this... any luck finding the resistance values for getting the IDC/MPS ratio around 50/50?

Thanks!

[Richard L]

R1 = 27K
R2 = 47K
R2/(R1+R2) is the ratio of IDC% (~63%)

http://www.aquamist.co.uk/HFS3/PI ratio.gif

[dscline]

Awesome, thanks! So if I understand correctly, 27K for R1 and 47K for R2 are the stock values? If you wanted to change the ratio to 50/50, for example, could you simply replace the stock R1 resistor with a 47K resistor (or R2 with a 27K), or is there also a requirement to keep the total resistance (R1+R2) something close to 27+47 (74K)?

[Richard L]

As long as the total valve is around 60-80K, it will be fine.
Don't forget to link MPS as well.

[dscline]

Understood, thanks!